The West Virginia taxable income of a resident estate or trust means its federal taxable income for the taxable year as defined in the laws of the United States and section nine of this article for the taxable year, with the following modifications:

(1) There shall be subtracted $600 as the West Virginia personal exemption of the estate or trust, and there shall be added the amount of its federal deduction for a personal exemption.

(2) There shall be added or subtracted, as the case may be, the share of the estate or trust in the West Virginia fiduciary adjustment determined under section nineteen of this article.

(3) There shall be added to federal adjusted gross income, unless already included therein, the amount of a lump sum distribution for which the taxpayer has elected under Section 402(e) of the Internal Revenue Code of 1986, as amended, to be separately taxed for federal income tax purposes: Provided, That the provisions of this subdivision shall first be effective for taxable years beginning after December 31, 1990.

(4) There shall be added by an electing small business trust as defined in Section 1361(e) of the Internal Revenue Code of 1986, as amended, which is a shareholder in one or more electing small business corporations, the portion of the trust's income attributable to electing small business corporation stock held by the trust that is not included in the trust's federal taxable income pursuant to Section 641 of the Internal Revenue Code of 1986, as amended.

(b) The amendments to this section enacted in the 2005 regular session of the Legislature are effective for tax years beginning on or after January 1, 2005.